抄録
Background: Ingesting a combination of caffeine and ephedrine (C+E) has been shown to raise metabolic heat production and body temperature. This side effect of C+E ingestion may be positive during a cold stress scenario, however, during heat stress it could prove to be detrimental. Thus, the purpose of this study was to clarify the effect of C+E ingestion on body temperature regulation during moderate exercise in a hot dry environment. Methods: Ten, healthy, non heat acclimated, males exercised at 50% V̇O2peak in a 40°C and 30% RH environment until rectal temperature reached 39.3°C; heart rate (HR) remained at 95% of peak value or greater for 3 min, dizziness or nausea precluded further exercise, or 3 h had elapsed. They did this four times at weekly intervals: familiarization (Fam), control (Cont), placebo, and C+E (5 mg · kg-1 caffeine + 1 mg · kg-1 ephedrine) trials. The Faro and Cont treatments were done first and sequentially while the placebo and C+E treatments were balanced and double-blind. Tolerance times, mean skin temperature (T̄sk), rectal temperature (Tre), V̇O2, V̇CO2, V̇E, sweat rate (SR), HR, and sensation of thermal comfort were measured. Results: Tolerance times (mean ± SD in minutes) were similar for the placebo (120.0 ± 28.4) and C+E (121.3 ± 33.9) trials and both times were significantly longer than Cont (106.6 ± 24.0) trial. C+E did not affect T̄sk, initial Tre, Δ Tre, SR or the sensation of thermal comfort. V̇O2 and V̇E, were significantly increased by C+E. HR was elevated by C+E compared with the other trials, but only during the initial 20 min of exercise. Conclusion: Although the metabolic rate was slightly increased with C+E treatment, it was sufficiently offset by increased heat loss mechanisms so that internal body temperature was not increased during moderate exercise in a hot, dry environment.
| 元の言語 | English |
|---|---|
| ページ（範囲） | 583-588 |
| ページ数 | 6 |
| ジャーナル | Aviation Space and Environmental Medicine |
| 巻 | 70 |
| 発行部数 | 6 |
| 出版物ステータス | Published - 1999 6 1 |
| 外部発表 | Yes |
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ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health
これを引用
Thermal regulation in the heat during exercise after caffeine and ephedrine ingestion. / Bell, Douglas G.; Jacobs, Ira; McLellan, Tom M.; Miyazaki, Masami; Sabtstdm, Catht M.
：: Aviation Space and Environmental Medicine, 巻 70, 番号 6, 01.06.1999, p. 583-588.研究成果: Article
}
TY - JOUR
T1 - Thermal regulation in the heat during exercise after caffeine and ephedrine ingestion
AU - Bell, Douglas G.
AU - Jacobs, Ira
AU - McLellan, Tom M.
AU - Miyazaki, Masami
AU - Sabtstdm, Catht M.
PY - 1999/6/1
Y1 - 1999/6/1
N2 - Background: Ingesting a combination of caffeine and ephedrine (C+E) has been shown to raise metabolic heat production and body temperature. This side effect of C+E ingestion may be positive during a cold stress scenario, however, during heat stress it could prove to be detrimental. Thus, the purpose of this study was to clarify the effect of C+E ingestion on body temperature regulation during moderate exercise in a hot dry environment. Methods: Ten, healthy, non heat acclimated, males exercised at 50% V̇O2peak in a 40°C and 30% RH environment until rectal temperature reached 39.3°C; heart rate (HR) remained at 95% of peak value or greater for 3 min, dizziness or nausea precluded further exercise, or 3 h had elapsed. They did this four times at weekly intervals: familiarization (Fam), control (Cont), placebo, and C+E (5 mg · kg-1 caffeine + 1 mg · kg-1 ephedrine) trials. The Faro and Cont treatments were done first and sequentially while the placebo and C+E treatments were balanced and double-blind. Tolerance times, mean skin temperature (T̄sk), rectal temperature (Tre), V̇O2, V̇CO2, V̇E, sweat rate (SR), HR, and sensation of thermal comfort were measured. Results: Tolerance times (mean ± SD in minutes) were similar for the placebo (120.0 ± 28.4) and C+E (121.3 ± 33.9) trials and both times were significantly longer than Cont (106.6 ± 24.0) trial. C+E did not affect T̄sk, initial Tre, Δ Tre, SR or the sensation of thermal comfort. V̇O2 and V̇E, were significantly increased by C+E. HR was elevated by C+E compared with the other trials, but only during the initial 20 min of exercise. Conclusion: Although the metabolic rate was slightly increased with C+E treatment, it was sufficiently offset by increased heat loss mechanisms so that internal body temperature was not increased during moderate exercise in a hot, dry environment.
AB - Background: Ingesting a combination of caffeine and ephedrine (C+E) has been shown to raise metabolic heat production and body temperature. This side effect of C+E ingestion may be positive during a cold stress scenario, however, during heat stress it could prove to be detrimental. Thus, the purpose of this study was to clarify the effect of C+E ingestion on body temperature regulation during moderate exercise in a hot dry environment. Methods: Ten, healthy, non heat acclimated, males exercised at 50% V̇O2peak in a 40°C and 30% RH environment until rectal temperature reached 39.3°C; heart rate (HR) remained at 95% of peak value or greater for 3 min, dizziness or nausea precluded further exercise, or 3 h had elapsed. They did this four times at weekly intervals: familiarization (Fam), control (Cont), placebo, and C+E (5 mg · kg-1 caffeine + 1 mg · kg-1 ephedrine) trials. The Faro and Cont treatments were done first and sequentially while the placebo and C+E treatments were balanced and double-blind. Tolerance times, mean skin temperature (T̄sk), rectal temperature (Tre), V̇O2, V̇CO2, V̇E, sweat rate (SR), HR, and sensation of thermal comfort were measured. Results: Tolerance times (mean ± SD in minutes) were similar for the placebo (120.0 ± 28.4) and C+E (121.3 ± 33.9) trials and both times were significantly longer than Cont (106.6 ± 24.0) trial. C+E did not affect T̄sk, initial Tre, Δ Tre, SR or the sensation of thermal comfort. V̇O2 and V̇E, were significantly increased by C+E. HR was elevated by C+E compared with the other trials, but only during the initial 20 min of exercise. Conclusion: Although the metabolic rate was slightly increased with C+E treatment, it was sufficiently offset by increased heat loss mechanisms so that internal body temperature was not increased during moderate exercise in a hot, dry environment.
KW - Ergogenic
KW - Heat stress
KW - Metabolism
KW - Methylxanthine
KW - Sympathomimetic
UR - http://www.scopus.com/inward/record.url?scp=0033016441&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033016441&partnerID=8YFLogxK
M3 - Article
VL - 70
SP - 583
EP - 588
JO - Aerospace medicine and human performance
JF - Aerospace medicine and human performance
SN - 2375-6314
IS - 6
ER -